Summary

The agronomic performance, biological nitrogen fixation (BNF) ability and self-establishment potential of seven species of annual self-reseeding legumes were investigated in Apulia region, Italy. For the first cropping cycle (2005-2006) preliminary results showed that Trifolium spp. performed better than Medicago spp. Among the seven species, five were more suitable to the site’s conditions. T. angustifolium and M. polymorpha gave the best results. T. angustifolium fixed 131.7 kg ha-1 year of nitrogen (15N isotope dilution method), produced 1976 kg ha-1 of seeds and 8.7 t ha-1 of dry matter (DM). M. radiata and M. rigidula were the less performing. During the second cropping cycle (2006-2007) results showed that Trifolium spp. self-established better than Medigaco spp. Regenerated species appeared to sustain optimum level of BNF. Again T. angustifolium was the best performing species producing the highest DM (7.7 t ha-1) and fixing nitrogen (146.7 kg) N ha-1 symbiotically. In contrast, M. polymorpha, was the less performing (0.3 t ha-1 of DM and 11.5 kg ha1 of BNF) while M. rigidula and M. radiata did not regenerate. Given the overall performance of all species, it was determined that T. angustifolium had the greatest potential for further development in this environment.